The objective of the project is to study effects of pharmacological agents and air pollutants on lungs and airways in man and animals. Changes of dynamic lung compliance and other mechanical parameters will be used to estimate such effects in man and in animals. The studies in animals are performed in spontaneously breathing guinea pigs using electronic data processing for breath-by-breath assessment of lung mechanics. Special attention is focused on individual differences in sensitivity to bronchoconstrictor agents in these animals, and we will attempt to relate these differences to their responses to air pollutants. This part of the project will include the study of pharmacological modification of the animal's sensitivity to bronchoconstrictor agents and air pollutants. This work develops a basic background for understanding of health effects of certain air pollutants on airway smooth muscle. It is well known that people exposed to various kinds of air pollutants differ greatly in the response they experience. We attempt to elucidate the mechanism that are responsible for this. Since it is unlikely that air pollution will ever be totally controlled, we must find ways of protecting those who are most sensitive to low levels of air pollution, and the present project is expected to help design such protection procedures.